Wordpress Fix Required: Can a Shortlink be by MLS Number?

I need to have control over the shortlinks that Wordpress assigns as I make a new blog entry for my listings. 

I have three Wordpress websites. Maintaining all three is getting to be a real nightmare.

I have a large number of listings, sometimes reaching seventy or more. I have a database that is keyed on the MLS numbers. It produces a page of my own listings. See it here. I want to expand the function of this page to lead to a full MLS report complete with pictures and virtual tours.

Is there a way to make Wordpress make a shortlink of the form http://seligmanaz.us/967409 rather than the one that works: http://seligmanaz.us//?p=431?  Since my database is already keyed on the MLS numbers, the ability to make the shortlink using the MLS numbers will save a lot of time in maintaining the database and keeping it current.